Marine steering-gear



T. McLEOD.

v MARINE STEERING GEAR.

APPLICATION FILED'AUGJB, 1917.

Patented Nov. 9, 1920.

2 SHEETS-SHEET I.

T. McLEOD.

MARINE STEERING GEAR APPLICATION FILED AUG-2B. m7.

1,353,454, Patented Nov. 9,1920.

2 SHEETS-SHEET 2. I

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Specification of Letters Patent.

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Patented Nov. 9, 192% 5 Application filed August Q8, 1917. serial No. 188.611.

To all whom it may concern Be it known that l, THOMAS Mol non, a

subject of the King of Great Britain and Ireland, and a. resident of the city and county of NeWcastle-upon-Tyne, England,

have invented certain new and usefulllmprovenients in or Relating to Marine Steer- 1 trolled by a by-pass device connected with the liquid transmission pipes. The object of the present invention is to provide an improved construction and arrangement of steering gear of this type.

According to the present invention 1 cmploy, for circulating the liquid operating the hydraulic rams, a fixed stroke duplex rotary pump adapted to run always in the same direction, and I arrange that said pump shall be normally driven by an electric motor so controlled by the handwheel or telemotor apparatus of the steering gear that no current is supplied to said motor when the handwheel or telemotor apparatus and the rudder are in mid-position, but the current is switched on so soon as the handwheel or telemotor apparatus is moved in either direction from its mid-position, the pump being thus driven'only when it is required. In cases of emergency or when desirable, the pump may he'driven continuously from the main engines of the ship or otherwise.

My invention allows the pumpand its driving motor to be arranged where most convenient, for. example, adjacent to the main engines, the leading of the liquid to and from the pump from and to the by-pass device and the current to and from the motor-controlling switch from and to the motor presenting no difficulties. The by-pass device may be arranged near to the hydraulic rams and the rudder arm, while the motor-controlling switch may be arranged in any position convenient to the handwheel or telemotor connections.

The accompanying drawings illustrate on arrangement'of steering gear embody ing the invention. In the drawings- Figure 1 is a diagrammatic plan view of the gear;-

Fig. 2 is a side View, partly in section, of the by-pass device;

Fig. 3 isa tace View, partly in section, of the icy-pass device;

Fig. l is a section of the duplex rotary pump; and

Figs. 5 and 6 are sections onthe lines X-X and Y-Y respectivelyin Fig. l.

Referring to the drawings, in the embodiment of the invention therein illustrated, I employ a duplex pump 1 comprising two sets of radialabutments or plungers 2, 3

provided upon a common sleeve or hollow shaft 4:. said plungers working within slidmg cylinders 5, 6 carried around within annular chambers 7, 8 eccentric with the sleeve l, the two sets of plungers 2, tl and cylinders 5, 6 being arranged side loy side. Within the sleeve 4:, is ried by the rear plate 10 of the pump casing. The front plate 11 of said casing forms a hearing for a shaft 12 in one with or connected to the sleeve 4, said shaft being directly coupled to the shaft 13 of an electric motor it as shown. in Fig. l, or it may be driven by a pulley and belt or otherwise conveniently from said motor. The two sets of plungers 2', 3 always rotate simultaneously and in the same direction. Flun' gers 2 deliver liquid to the cylinder 42, and plungers 3 to the cylinder ll. When one set of plungers is delivering liquid to its cylinder, the liquid from the other set is circulating through a hy-pass valve as hereinafter described. Each set may comprise two, four or more radial plungers. independent inlet and outlet ports are provided for each set of plungers in thefixed boss 9.

In the construction illustrated in the drawings there are four radial plungers in each set, an inlet port 15 and outlet port 16 being provided for the plungers 2, and an inlet port 17 and outlet port 18 for the plungers 3. The outlet ports 16, 18 communicate with separate discharge pipes 19, 20 respectively and the inlet ports 15, 17 communicate withseparate suction pipes 22 and 21 respectively. I

The lay-pass device 23 is ,constructed and operated substantially as described in the specification of my previous British Patent No. 22738, A. D. 1911, and comprises two spring-pressed valves 24, 25, one for each of the discharge pipes 19, 20 said pipes connecting the outlet ports 16, 18 of the rotary pump 1 with the chambers 26, 27 above said valves. The suction pipes 21, 22 connect the suction chamber 28 of the by-pass device (which is common to both the 1 valves 24, 25) with the inlet ports 15, 17 of the pumpl. The suction chamber 28 is connected by a pipe 29 (Fig. 3) to a liquid supply tank or reservoir 30 through a suction valve 31. 32 is the rocker adapted to open the valves 24, 25, said rocker being mounted on one end of a spindle 33 on the other end of which is fixed a lever 34 connected by link mechanism 35, 35 to the centralcrosshead 36 of the rudder operating rams 37, 38. The liquid transmission pipes 39, 40 to the two hydraulic cylinders 41, 42 open one out of each of the chambers 26,

'27 above the by-pass'valves 24, 25, Lever 34 is also connected to a link 43 adapted to be operated by the usual telemotor apparatus or handwheel to actuate rocker 32. With rocker 32 in normal or central position both valves 24 and 25 are openas shown in 3, but when the rocker is-actuated 1n e1ther d1rection it further opens one of said valves and allows the other to close under its spring.

is not reversed when the switch arm 46 passes from one set of contacts to the other across the central interval or space. Preferably the switch is of the step-by-step con troller type so that, as the arm 46 is moved farther from mid-position ineither. direction, the current to the motor 14 is correspondingly increased, but, if desired, in-.

stead of two sets of contacts such as 44, 45, two single contacts maybe used. i

The switch arm 46 is pivoted at 47 and provided with a toothed quadrant 48 which is engaged by a worm 49 on a shaft 50 coupled through bevel gearing'51, 52 with a shaft 53 having a threaded portion 54. The threaded portion 54 engages a nut 55 connected by links 56 to the link 35. forming a part of the mechanism connecting the rocking spindle 33 which operates the bypass valves 24, 25 to the central crosshead 36 of the hydraulic rams 37, 38. The links 56 restrain the nut 55 from rotary movement.

The crosshead 36 is pivoted at 57 to a trunnion block 58 slidably mounted on the intense rudder tiller 59 and when the crosshead 36 (and hence the rudder) is in mid-position (as illustrated in Fig. 1) rocker 32 and switch arm 46 are also in mid'positiomboth by-pass valves 24, 25-are open,'the current to the motor 14 is cut off, and the pump 1 is not in action. So soon as'the hand wheel or telemotor apparatus is moved from mid position to one side or the other, link '43 is operated and actuates lever 34, spindle 33 and rocker 32 tofurther open one of the valves 24, 25 and allow the other to close under its spring. Simultaneously, link 43 also moves link 35 which moves the links 56 to cause the nut 55 to co-act with the threaded portion 54 of the shaft 53 to rotate said shaft and the worm shaft 50 which ro tates the switcharm 46to cause the latter to make contact with a contact of one set of contacts 44 or 45, and current passes to the motor 14 and the pump 1 is driven thereby, the direction of the flow of the liquid to the c linders 41, 42 of the hydraulic rams 3;, 38 depending upon the direction in which link 43 is operated and which of valves 24, 25 is allowedcto close and which is further opened. When one 'by-pass valve isclosed, one set of pump plungers circulates the liquid-to and from the ramcylinders, the other set of pump plungers' merely. circulatin the liquid through the by-pass device. hus, with bypass valve 24 closed and valve 25 open, pump plungers 2 circulate the liquid from cylinder 41 of 'ram'j37 to cylinder 42 of ram 38 and-pump plungers 3 merely-circulate liquid from byasssuction chamber 28 to valve chamber 2 .and past valve 25. With by-pass valve 25 closed and valve 24 open, pumpplungers 3 circulate the liquid from cylinder 42 of ram 38 to cylinder 41 of ram 37 and plungers 2 merely circulate liquid from suction chamber 28 to valve chamber 26 and past valve 24. a

As the crosshead 36 and'tiller 59 move in either direction from mid-position, links 35, 35 operate to restore rocker 32 to central position and open both by-pass valves 24,25 when the rudder reaches the position corresponding to the movement of the telemotor apparatus or handwheehin a similar man ner to that in which the hunting gear of a steam steering gear operates'to restore the controlling valve to mid-position on the rudder reaching the position corresponding to the movement of the telemotor apparatus or handwhe'el. 1

By my invention I obtain a considerable saving of current compared with the usual continuously driven pumps, and, moreover, where a step-by-step controller switch is used, the current supplied to the. pumpdriving motor will be automatically varied with the amount of movement to be imparted to the rudder.

Should the motor break down or its bat when the rudder is in mid-position, the

liquid from the pump will merely circulate through the by-pass device.

As will be obvious, instead of the telemotor or handwheel connection 43 being connected to lever 34 of rocking spindle 33, it might be connected to link 35 orlinks 56 without alteration in the Working of the gear.

What I claim as my invention, and desire to secure by Letters Patent is 1. A hydraulic marine steering gear comprising two hydraulic rams to move the rudder, a pump for forcing liquid to and from the rams, a controlling valve deter- 20 mining the direction of movement of the rams,a motor for driving said pump and adapted to always rotate in the same direction, and means for simultaneously setting said valve and starting said motor.

2. A hydraulic marine steering gear comprisingtwo hydraulic rams connected tomove the rudder, a duplex pump, a liquid. circulatory system between the pump and rams, whereby the two stages of the pump will circulate liquid in the respective rams, and a bypass valve in said system for determining which of said stages shall be active.

In witness whereof I have hereunto set my hand.

THOMAS MoLEOD.

Witnesses:

FRED IRWIN, ERNEST E. ENGLAND. 

